Multiple-flow vane cell pump

ABSTRACT

A multiple-flow vane cell pump which includes at least two points (openings) along the rotational direction of the rotor, at which there is essentially the same pressure during operation and which are spaced apart from inlets and outlets and are hydraulically connected to each other (connection).

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is a United States national phase patent application based on PCT/DE2020/200101 filed on May 22, 2020, which claims the benefit of German Patent Application No. DE 10 2019 218 034.5 filed on Nov. 22, 2019, the entire contents of both of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The invention relates to a multiple-flow vane cell pump. Vane cell pumps are frequently used, for example in the automotive field, in order to convey hydraulic fluids, in particular oil. These types of pumps can be used as power steering or transmission pumps, for example.

BACKGROUND ART

A vane cell pump of this type is known from DE 1 553 283 A and comprises a hydraulic connection between the point of the smallest distance from the rotor axis and the point of the largest distance from the rotor axis.

U.S. Pat. No. 9,366,251 B2 relates to a multiple-flow vane cell pump. Said pumps usually have a symmetrical structure; in other words, a plurality of pumps are arranged around the rotor axis, each with a suction region and a discharge region. The hydraulic and mechanical forces thereof can thereby balance each other out, and transverse forces do not occur, at least in theory, either on the rotor, or on the shaft thereof, or on the surrounding stroke ring. In practice, however, manufacturing-related tolerances lead to said components and the geometry thereof not being symmetrical. This generates asymmetrical pressures and thus asymmetrical forces during operation. Similar effects are caused by air bubbles in the conveyed oil or an uneven supply of oil to the suction regions. As a result of such imbalances in terms of forces, there is increased noise and wear. To date, this has been counteracted by comparatively narrow tolerances and/or notches at the pressure outlet in order to keep pressure fluctuations low.

DESCRIPTION OF THE INVENTION

Against this background, the object of the invention is to provide a multiple-flow vane cell pump that is improved with regard to noise and/or wear.

This object is solved by the multiple-flow vane cell pump described herein.

Said pump is thus characterized in that at least two points along the rotational direction of the rotor, at which there is essentially the same pressure during operation and which are spaced apart from inlets and outlets, are hydraulically connected to each other. In other words, the measure according to the invention differs from the conventional measure in multiple-flow or multiple-stroke vane cell pumps, i.e. to respectively connect the plurality of inlets and outlets to each other. According to the invention, regions within the vane cell pump which, at least in theory, have the same cell pressure and are spaced apart from inlets and outlets are instead hydraulically connected to each other. Imbalances in terms of pressure, whatever the cause thereof, can thereby be at least partially compensated and equalized so that noise and wear are advantageously reduced.

As will be explained below in more detail, this is possible by means of comparatively low-cost measures. In this regard, the number of flows provided in the pump according to the invention is arbitrary; it can in particular be a two-, three-, four- or multiple-flow vane cell pump. In a two- or four-flow vane cell pump or in another vane cell pump comprising an even number of flows, cells that are diagonally opposite one another are connected, and in a three- or five-flow pump, the cells are connected, for example, which are evenly spaced apart from each other by 120° or 72°, in any case, in a circumferential direction.

The hydraulic connection is preferably configured in the form of openings, in particular bores and/or grooves in the rotor and/or in the stroke ring and/or in at least one side plate. Suitable grooves may in particular be provided in the stroke ring, which are metallically sealed by the side plates. Openings can furthermore be formed in the side plates, for example they can be bored or formed by means of an additive manufacturing method. The same manufacturing methods are suitable for forming openings in the rotor to produce the hydraulic connection according to the invention. Said connection can in particular be configured between all cells in which, in theory, there is the same pressure during operation, or by connecting only some of these cells. If openings or the like are formed in the rotor, the advantage is that the connection according to the invention is always present, whereas if openings or the like are formed in the stroke ring or in a side plate, the connection is interrupted when a vane of the pump passes over the opening provided for the hydraulic connection. However, this is not expected to have a significant impact on the effect according to the invention.

The effects according to the invention can be used particularly extensively if at least two openings or grooves have the same distance from the rotor axis. This additionally simplifies manufacture.

A particularly good functionality and manufacturability is expected for at least one radially extending bore or groove and/or one axial opening, in particular if it is formed in a linear manner.

In other cases of use, weakening of the rotor and the side plates can be advantageously avoided by means of a connection that extends in particular in the stroke ring and is at least partially configured in the circumferential direction.

In this case, the preferred measure does not require more space if at least one connection is designed to surround a pin.

It is furthermore advantageous with regard to handling and assembly of the pump according to the invention if said pump comprises a lid that closes the side plate and/or a housing that is essentially pot-shaped.

An additive manufacturing method furthermore has advantages as regards the formation of the, at least in specific cases of use, comparatively complex shapes which form the connection according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention is explained in more detail by reference to exemplary embodiments depicted in the figures. These show as follows:

FIG. 1 a hydraulic schematic diagram of a first embodiment of the pump according to the invention.

FIG. 2 a cross-sectional view of a second embodiment of the pump according to the invention.

FIG. 3 a longitudinal sectional view of a pump according to the invention, similar to the first embodiment.

FIG. 4 a cross-sectional view of a third embodiment of the pump according to the invention, and

FIG. 5 a cross-sectional view of a fourth embodiment of the pump according to the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As is apparent in FIG. 1 , the vane cell pump 10, which is a two-flow vane cell pump in the illustrated case, conveys hydraulic fluid from a reservoir 12. For this purpose, two lines 14 to the respective suction or inlet regions 16 are formed, and, in a similar manner, two lines 18, which are connected to each other, extend from the respective outlet region 20.

The structure of the vane cell pump 10 is explained in more detail below with reference to FIG. 2 . However, it is apparent in FIG. 1 that regions or cells that are spaced apart from the inlet 16 and the outlet 20 and that are diametrically opposite each other owing to the configuration of the pump as a two-flow vane cell pump are hydraulically connected to each other by means of the shown connection 26. In the case shown, openings 28 are formed for this purpose in a side plate (40; cf. FIG. 3 ). The arrow in the region of the rotor indicates the direction of rotation.

In FIG. 2 , the direction of rotation is opposite to that of FIG. 1 . FIG. 2 shows a three-flow vane cell pump 10, which comprises, in a known manner, a rotor 30 with slits 32, in which one vane 34 each is accommodated in a movable manner in the radial direction. In accordance with the three-flow configuration, the embodiment of FIG. 2 comprises three inlets 16 and three outlets 20. These are formed in a stroke ring 36 in a known manner. In accordance with the embodiments shown in FIG. 1 , points which are spaced apart from inlets 16 and outlets 18 and at which there is, in theory, the same pressure are provided with openings 28 in order to hydraulically connect them to each other. According to the three-flow embodiment of the vane cell pump shown in FIG. 2 , said openings 28 are spaced apart from each other by 120°. The preferred measure according to which the openings have the same distance from the rotor axis is moreover apparent.

As is apparent in FIG. 3 , a connection 26, which is schematically drawn in FIG. 1 , is configured in one of the side plates 40 in the form of a radially extending groove and connects the two openings 28 to each other. The side plate 40 that is provided with the groove is closed by a lid 42, and the lid 42 is accommodated in an essentially pot-shaped housing 44, together with the two side plates 40, the rotor 30 and the stroke ring 36.

Although this is not shown in the three-flow pump provided in FIG. 2 , the connection according to the invention can also be configured in the form of radial connections in the rotor 30 or, in the stroke ring 36, in the form of a connection extending in a circumferential direction between three cells, as is described below with regard to a two-flow vane cell pump and illustrated in FIGS. 4 and 5 .

In FIG. 4 , a vane cell pump 10 that is similar to the embodiment of FIG. 1 is provided, in which, however, the connection 26 is configured for the aforedescribed pressure compensation in the rotor 30 and in particular also the shaft 38 thereof. The connection 26 is advantageously configured as a continuous bore that extends in a linear manner. In order to have complete pressure compensation in the region of all of the cells, the connection would have to be repeated for each pair of cells.

Finally, a further embodiment is apparent in FIG. 5 , in which the connection 26 is configured in the stroke ring 36. As is apparent in FIG. 5 , the connection 26 is configured over a wide course in a manner concentric to the outer contour of the stroke ring 36, and is connected to the respective cell of the pump by means of a short radial connection. In the bottom part on the left of FIG. 5 , it is apparent that said connection 26 can be configured to surround a pin which is shown as a circle. 

1.-10. (canceled)
 11. A multiple-flow vane cell pump comprising: a plurality of spaced apart inlets; a plurality of spaced apart outlets; a rotor including at least two openings formed along a rotational direction of the rotor, wherein at the openings there is essentially a same pressure during operation and the at least two openings are spaced apart from the inlets and the outlets, and wherein the at least two openings are hydraulically connected to each other by at least one connection.
 12. The multiple-flow vane cell pump according to claim 11, wherein the at least two openings are bores or grooves in one of the rotor, a stroke ring, or at least one side plate.
 13. The multiple-flow vane cell pump according to claim 12, wherein the at least two openings are a same distance from an axis of the rotor.
 14. The multiple-flow vane cell pump according to claim 12, wherein at least one of the bores or the grooves extends radially and/or at least one of the at least two openings is formed axially.
 15. The multiple-flow vane cell pump according to claim 14, wherein at least one of the at least one bores, the grooves and the at least two openings is formed in a linear manner.
 16. The multiple-flow vane cell pump according claim 11, wherein the at least one connection extends at least partially in a circumferential direction.
 17. The multiple-flow vane cell pump according to claim 11, wherein the at least one connection surrounds a pin.
 18. The multiple-flow vane cell pump according to claim 11, wherein at least one side plate is closed by a lid.
 19. The multiple-flow vane cell pump according to claim 11, wherein the pump further comprises a pot-shaped housing.
 20. The multiple-flow vane cell pump according to claim 11, wherein the at least one connection is produced by an additive manufacturing method. 